|The lorry which the body were found.|
At least 20 migrants have been found dead in a lorry abandoned ina motorway lay-by near the eastern border with Hungary, the Austrian authorities say.
The number of dead could be as high as 50, police say. Their bodies had started to decompose.
The lorry has been moved to an undisclosed location for detailed examination.
The grim find comes as a summit focusing on migration takes place in the Austrian capital, Vienna.
Tens of thousands of migrants from conflict-hit states in the Middle East and Africa have been trying to make their way to Europe.
Austria's Chancellor Walter Faymann said the tragedy showed once again "how necessary it is to save lives by combating criminals and people traffickers".
The vehicle - a refrigerated lorry with Hungarian licence plates - was parked off the A4 motorway between Parndorf and Neusiedl am See, according to Burgenland police chief Hans Peter Doskozil.
Officers had found at least 20 bodies inside the lorry, but there could be 30, 40 or even 50 inside, he told Austrian TV.
The vehicle was found on Thursday morning but had been there since at least Wednesday, Mr Doskozil said.
The victims had been dead for some time.
Mr Doskozil described the incident as a "terrible crime".
Organised criminals had turned people into commercial transactions, he said.
The truck bears the logo of a Slovakian poultry company, Hyza, which said in a statement that the vehicle no longer belonged to the firm - but the new owners had not removed the branding.
Hungarian police are working with Austrian police on the investigation, a spokesman for the Hungarian prime minister said.
Hungary had been informed that the driver was Romanian, the spokesman said.